Lombard paradox

The Lombard paradox describes an apparently paradoxical function of the ischiocrural muscles in humans from the standpoint of classical anatomical function ascription .

The phenomenon was described by the US physiologist Lombard at the beginning of the 20th century . The “paradox” here is seen in the fact that when the foot and / or the pelvis are fixed, the ischiocrural muscles help stretch the knee joint . According to the classical understanding, this function is attributed to the muscles of the front of the thigh ( muscle quadriceps femoris ), which according to this has an antagonistic function to the ischiocrural muscles . The physician Klaus Wiemann writes, among other things:

"When comparing the physiological cross-section of the hamstring muscles with the tasks to be performed in the knee joint, which are generally expected of these muscles in the course of everyday motor skills (bending of the knee joints), it was noticeable that the enormous maximum possible muscle force moment in no logical relation to the comparatively low load torque to be mastered z. B. stands when bending the knees in the swing phase in the course of walking and running cycles. For this reason, it had to be assumed that the sciocrural muscles in everyday motor skills have additional, previously unrecognized tasks or that their mode of action was not correctly assessed. In corresponding literature research, articles by Lombard (1903), Gregor et al. (1985) and ANDREWS (1987) were found which could also provide an explanation for the problem of the function of the hamstring muscles during sprinting. "

literature

• WP Lombard, FM Abbott: The mechanical effects produced by the contraction of individual muscles of the thigh of the frog. In: American Journal of Physiology . 20, 1907, pp. 1-60.
• moon.ouhsc.edu

• Klaus Wiemann: Clarification of the LOMBARD paradox in the function of the hamstring muscles during sprinting. (PDF; 179 kB)
• JG Andrews: The functional roles of the hamstrings and quadriceps during cycling: Lombard's Paradox revisited . In: J Biomech . tape 20 , no. 6 , 1987, pp. 565-575 , doi : 10.1016 / 0021-9290 (87) 90278-8 , PMID 3611133 .
• RJ Gregor, PR Cavanagh, M. LaFortune: Knee flexor moments during propulsion in cycling - a creative solution to Lombard's Paradox . In: J Biomech . tape 18 , no. 5 , 1985, pp. 307-316 , doi : 10.1016 / 0021-9290 (85) 90286-6 , PMID 4008501 .

Individual evidence

1. ↑ WP Lombard in: Nature 144, 1084-1085 (30 December 1939)
2. ^ "Paradoxical functions" of bipartite skeletal muscles